Friend Needs 1970 340 Heads - Advice?
#2995574
12/15/21 05:55 PM
12/15/21 05:55 PM
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Joined: Jan 2003
Posts: 8,398 Highland, MI.
Sunroofcuda
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Highland, MI.
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So my buddy bought a 70 Challenger 340 back in the spring & the car had a running 318 in it, but the original 340 came with it. He just found out the heads are no good. So what would be y'alls advice on what to do heads-wise? Look for a good original set, or aftermarket? If aftermarket, which heads?
Thanks for the advice.
Last edited by Sunroofcuda; 12/15/21 05:56 PM.
No Man With A Good Car Needs To Be Justified
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Re: Friend Needs 1970 340 Heads - Advice?
[Re: Rhinodart]
#2995671
12/15/21 11:08 PM
12/15/21 11:08 PM
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Joined: Jan 2003
Posts: 8,398 Highland, MI.
Sunroofcuda
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His engine guy in CA. checked them out - I don't think either of us know the minute details. I'm guessing they are cracked. He said the heads are junk.
No Man With A Good Car Needs To Be Justified
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Re: Friend Needs 1970 340 Heads - Advice?
[Re: Sunroofcuda]
#2995697
12/16/21 02:38 AM
12/16/21 02:38 AM
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Joined: May 2006
Posts: 1,757 Phila
PhillyRag
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running 318 in it, but the original 340 came with it. He just found out the heads are no good Which heads are junk? Find some nice mid-70's or so nice 360 heads. Hopefully from some full size car that hasn't been "raced". But not the smog ones. Lots of 340's were driven hard early on. After all: the 340-6 heads were based on a 360 head casting. X-heads seem to have some "mystical" following, that ups the price for them. Once installed, the difference is visibly nil.
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Re: Friend Needs 1970 340 Heads - Advice?
[Re: PhillyRag]
#2995702
12/16/21 06:26 AM
12/16/21 06:26 AM
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Joined: Nov 2020
Posts: 348 Isle of Sheeps
Gtxxjon
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Plenty of 'J Heads' around... If they were good enough for the T/A engines they is good enough for me lol... Yes they do crack across, to the spark plug mainly on the intake seat. I have run them like this, but a new seat would easily fix this problem. They can be ported to easily run 400hp and more! This is me copying a Weslake Engineering Demo cutaway J-head from 1970...
Last edited by Gtxxjon; 12/16/21 06:34 AM.
Carpe diem, quam minimum credula postero, thanx Horace!
There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...
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Re: Friend Needs 1970 340 Heads - Advice?
[Re: Gtxxjon]
#2995704
12/16/21 06:46 AM
12/16/21 06:46 AM
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Joined: Nov 2020
Posts: 348 Isle of Sheeps
Gtxxjon
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The old Mopar performance book... The best advice for iron heads on the Planet! Once you read this, all the new stuff is just Chinese copies lol... Everything that is around now was done over 50 years ago,,, 'ALREADY' LOL... Bob Mullen the god of small block iron heads... YES that top picture says 500 horses, 'back in the day'...
Last edited by Gtxxjon; 12/16/21 06:50 AM.
Carpe diem, quam minimum credula postero, thanx Horace!
There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...
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Re: Friend Needs 1970 340 Heads - Advice?
[Re: poorboy]
#3002953
01/07/22 06:03 PM
01/07/22 06:03 PM
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Joined: Jan 2003
Posts: 8,398 Highland, MI.
Sunroofcuda
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Maybe the guy running the shop that said your heads are junk has a buddy that wants them, or may already have them... If you want them back, he will send you the busted heads off his buddy's motor. Yes - most likely! OK, so he has found a set of 340 heads advertised. I'll post the info & photo - does he want these, or not?
No Man With A Good Car Needs To Be Justified
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Re: Friend Needs 1970 340 Heads - Advice?
[Re: Sunroofcuda]
#3003081
01/08/22 06:58 AM
01/08/22 06:58 AM
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Joined: Jan 2003
Posts: 6,418 Abilene, Texas
fastmark
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Maybe the guy running the shop that said your heads are junk has a buddy that wants them, or may already have them... If you want them back, he will send you the busted heads off his buddy's motor. Yes - most likely! OK, so he has found a set of 340 heads advertised. I'll post the info & photo - does he want these, or not? Until you get your old heads and find out why then were condemned, you may be wasting money on onother set of heads. First find that out. If you can’t deal with that shop, get another one. You have to find a good machine shop that you can trust and communicate with first. The heads my customer has are 915 from a 71 340 with 2.02 valves. I sent them to the machine shop for minor repair and then after they were fixed, he changed his mind and wanted a 4.00” stroke motor with alum heads. So we spent almost $900 on heads we will not use. They have been decked, magnufulxed, HP valve job, cut for the best seals and assembled with springs. I use a very good shop. He does excellent work. He does not work for nothing or steal parts. I figure these to be worth $900-$1000 is all. I don’t know what your friends budget is. Usually budget work bites you in the but. These used heads may be small valve 360 heads not 340 heads so you’ll have to buy new valves right off. You don’t know what condition they are in in the first place. The price is very fair if they are good cores. I’ve got plenty of cores like that.
Last edited by fastmark; 01/08/22 07:00 AM.
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Re: Friend Needs 1970 340 Heads - Advice?
[Re: fastmark]
#3003144
01/08/22 12:32 PM
01/08/22 12:32 PM
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Joined: Jul 2011
Posts: 960 Chicago
PurpleBeeper
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If it was ME (which it isn't), I'd look for a set of heads like fastmarks and just swap them out if building a street motor. If I've got extra cash, I'd buy some aluminum heads. My last choice would be rebuilding the original heads unless the car is a "numbers car" and the head is somehting special on your car, which I don't think is the case. My 2-cents
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'04 4.6 SOHC, NOS, auto, lowered
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Re: Friend Needs 1970 340 Heads - Advice?
[Re: PurpleBeeper]
#3003185
01/08/22 02:50 PM
01/08/22 02:50 PM
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Joined: Sep 2003
Posts: 19,485 north of coder
moparx
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"Butt Crack Bob"
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If it was ME (which it isn't), I'd look for a set of heads like fastmarks and just swap them out if building a street motor. If I've got extra cash, I'd buy some aluminum heads. My last choice would be rebuilding the original heads unless the car is a "numbers car" and the head is somehting special on your car, which I don't think is the case. My 2-cents ^^^^^^ as to the rebuild vs new aluminum heads, i would just bite the bullet and get the aluminum heads. rebuilding the old iron pieces and doing them right, you will have as much, and most likely more money invested. unless, of course, this NEEDS to be a numbers build. [as has already been mentioned] just my opinion as well. your mileage will vary.
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Re: Friend Needs 1970 340 Heads - Advice?
[Re: moparx]
#3004047
01/11/22 08:27 AM
01/11/22 08:27 AM
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Joined: Nov 2020
Posts: 348 Isle of Sheeps
Gtxxjon
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Very sound advice indeed!
Without a machine shop you can trust, you are in deep poo-poo! Realistically a full re-vamp of any iron head is $500 per side.
You can buy a new aussie iron head and fit the parts yourself, $350...
Or for $1800 you can buy an Edelbrock or trickflow ali head.
Most folks would always say ''go new'' its not worth messing with 50 year old JUNK!
Last edited by Gtxxjon; 01/11/22 08:28 AM.
Carpe diem, quam minimum credula postero, thanx Horace!
There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...
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